WMG / Lethal Weapon

Riggs is losing his eyesight.
He's shown to have Improbable Aiming Skills throughout the films. Why else would he even need a Laser Sight in the fourth.

The Flamethrower guy is a Cleaner
Through some quirk of the game or whatever, he's dropped into 1998 still trying to burn out the Dollar Flu, regardless who's in his way.